The demand for secondary batteries such as lithium ion secondary batteries that are lightweight and have high output is expected to rise steadily as power supplies installed in vehicles and as power supplies for personal computers and mobile terminals. A typical example of such secondary batteries is one in which positive and negative electrode sheets are laminated into an electrode assembly, which is housed in a battery container along with a nonaqueous electrolyte solution. Patent Document 1 is given here as an example of a prior art publication related to this type of nonaqueous electrolyte solution secondary battery.    Patent Document 1: Japanese Patent Application Laid-Open No. 2005-228511